Stapling machine



Oct. 19, 1937. g, A, CROSBY 2,096,573

' STAPLING MACHINE Filed Jan. 27, 1934 5 Sheets-Sheet l INVENTOR N 4 ATTORNEYS Oct. 19, 1937. s. A. CROSBY 2,095,573

STAPLING MACHINE Filed Jan. 27, 1954 3 Sheets-Sheet 2 A B V n a (I n l. g "Iii/u c 6' l in 52 B E 39 g 7 Oct 19, 1937. CROSBY 1 2,096,573

STAPLiNG MACHINE Filed Jan. 27, 1934 5 Sheets-Sheet 3 u/Ml ,M 10.49 M ATTORNEYS Step/am fl. Gwy

Patented Oct. 19, 1937 UNlTED STATES PATENT OFFICE STAPLING MACHINE Stephen A. Crosby, New York; N. Y., assignor to Parrot Speed Fastener Corporation, New York, N. Y., a corporationof New York Application January 27, 1934, Serial No. 708,541

22 Claims.

ment; an improved construction of the staple supporting arm; improved constructions of the stapling arm and associated parts permitting easy assembly of the staple guide rail and the rear and front staple guide plates in the staplingarm and an improved connection between the driving plunger and the staple driving and setting plate.

Other objects of the invention will appear from the following description taken in connection with the drawings which, for the purposes of illustration, disclose a preferred embodiment of my invention, .and in which Fig. 1 is a side elevation of my improved stapling machine;

Fig. 2 is a front elevation thereof;

Fig. 3 is a rear elevation thereof;

Fig. 4 is a top plan View thereof;

Fig. 5 is a longitudinal central vertical section taken on the line 55 of Fig. 4;

Fig. 6 is a section similar to that of Fig. 5 but showing only a. part of the mechanism therein disclosed with the driving and setting plate and staple supporting arm in their lowermost position;

Fig. '7 is a view similar to Fig. 6 showing the driving and setting plate and staple supporting arm during their return movement;

Fig. 8 shows the connection between the driving plunger and the driving and setting plate;

Fig. 9 is a longitudinal horizontal section through the stapling arm;

Fig. 10 shows the staple-guide rail and the rear staple guiding plate in assembled relation;

Fig. 11 is a perspective view of the front staple guiding plate;

Fig. 12 shows the return spring for the stapling arm;

Fig. 13 is a vertical section through the driving plunger and head of the stapling arm;

Fig. 14 is a vertical section through the follower spring and head of the stapling arm; and

Fig. 15 shows the spring retaining and driving plunger arresting means.

In the drawings I have illustrated a preferred embodiment of the invention which will be described in detail, but it is to be distinctly 'understood that various changes may be made without departing from the spirit of the invention, and that the embodiment selected for illustration has merely been chosen for the purpose of describing the principles of the invention.

The stapling machine disclosed includes a base A, apivoted stapling arm B, and a vertically movable driving plunger C.

:The base A, shown incross section in Fig. 5, maybe cast or formed in the shape shown. It

includes atop plate I and a surrounding flange 2,-which may be shaped as shown. Near its front end, the top plate I is provided with a depression in which is seated an anvil 3 provided with the usual clinching slot,.as indicated. The anvil may be secured in position by rivets or the like as indicated, which project beyond the lower face of the top plate: I a suflicient distance to provide anchoring means for a rubber foot 4. 'The rear end of the base is provided with parallel slots through H which project ears 5 and 6 which support the pivot bolt :1 on which the arm Bis pivoted. These earsare itormed on a plate 8 secured against the bottom surface of the top plate I by rivets 9 and Id. Studs .ll riveted in plate I constitute means for holding the rubber feet l2 in position. The rivet It! also secures the stapling arm return spring l3 to the base, as indicated in Fig. 5. This spring is preferably made of flat stock and is extended upwardly into position to be engaged by the arm, and then downwardly through slots in the base plate I and'plate 8 in which it operates as the arm is operated, and then in the form of a semicircle and extended toward the rear of the base to engage with the lower-face of the plate 8. The upwardly :bent portion of the spring engages in seats I4 in the lower edges of the side members of the stapling arm B.

The staplingarm B disclosed comprises a single casting which includes a housing for the follower spring,a housing and guiding portion. for the driving plunger and its spring, a portion for receiving the front staple guide plate, and the rear staple guide plate and the staple guide rail.

' The rear portion of the arm comprises parallel spaced members l5 and I6, each of which is provided with an inturned flange, as indicated at I and I8, at its upper edge, the lower faces of which constitute retaining andgguiding shoulders for the staple strip [9 and the staple follower 20. As-indicated in Figs. 5, 13 and 14, the front end or main portion of the housing is provided with shoulders 21 and 22, of which the lowerfaces of the inturned flanges I1 and I8 constitute, in effect, continuations.

The rear ends of the side members l5 and I6 are preferably integrally connected by a crossmember 23 located directly to the rear of the pivot holes for the ,pivot pin 1. Formed on the top of the member 23 is a substantially rectangular projection 24 which constitutes a centering device and support for the rear end of the staple guide rail 25, see Figs. 3, 5, 10 and 9. The rail 25 maybe U-shaped in cross section, as shown in Fig. 10, and the rear ends of the side members of the member 25, are provided with lone.

see also Figs. 5 and 9, which permit relative longitudinal movement between the rail 25 and the stapling arm for the purpose of assembly. The

vertical dimension of these slots is the same as the diameter of the pivot to accurately position the rail vertically with respect to .the' guiding shoulders on the flanges I! and 18, before referred to.

As shown in Fig. 1.0 a rear staple guide plate 36 is preferably provided with a vertically extending portion 3! fitting within'the front end of the staple guide rail 25, and with laterally projecting shoulders 32 and 33 which fitin notches in the side members of the rail, and with lower relatively long laterally. extending portions 34 and 35 which fit in notches in the corners of the side members of the rail. When the parts are assembled, the projectionsx32 and 33 terminate slightly within the outside faces of the side members of the railyand the flanges 34 and 35 engage in grooves 35 and3'l, Fig. 9, and by their engagement with the bottoms of these grooves center the front end of the rail. The upper sides of the flanges 34 and '35 are. preferably beveled, as indicated in Fig. 10, to guide staples that have been severed from the strip into the staple guide or raceway 38 of the frontstaple guide plate 39, Fig. 11.

The staple guide rail 25 is assembled with the stapling arm 13 by inserting the rear end of the rail within the channel inthe arm, and moving the. rail to the rear until the rear end engages over the projection 24, after which the front end is locked in position by a pin 40 whichalso constitutes the means for anchoring one end of' the spring 45, the other end'of which is anchored to the rear end of a staple supporting arm 42 pivoted on a pin 43 supported in the forward and narrow ends of slots 43' in the side walls of the rail, as indicated on the drawings. The slots 43' are provided with enlarged communicating portions 44' to permit the assembly of the pin with the arm. The front elongated portions of the slots cooperate with the shoulders or steps 45' formed by necks or reduced portions 46' on the pin 43 to hold the pin in assembled position.

After the staple guide rail 25 has been assembled as indicated, the front staple guide" plate or race liner 39, Fig. 11, is placed in position and is secured in place by a screw bolt 44. passing through a slot 45 in the guide plate, as indicated in Fig. 11. The stapleraceway or groove 38 is preferably provided with an enlarged portion 46, as indicated in Fig. 11, in order to prevent clogging as the staples are fed forwardly beneath the staple driving and setting plate or blade 41, when this plateis in' the position'indicated in Fig. 5. The lower part of the walls. of the enlarged portion of the vertical groove'38 is preferably tapered, as indicated at 48, to guide the staple into the lower end of the groove 38 as the staple driving and setting plate. 41 is moved downwardly. The plate or race block 35' is also provided with a vertically disposed clearance groove 49 for the front end of the plunger C. As indicated in Fig. 9, the front guide plate 39 is held in centered relation by the side walls of the grooves 36 and 31, and its rear face is held in engagement with the rear guide plate by the front walls of these grooves.

The staple supporting arm or trigger 42 is in the position shown in Fig; 5 when'the driving and setting plate or blade 4? is in its uppermost H .,p0,sition. As the driving and setting plate 4'! is gitudinally elongated slots such as 26 inVFig. 1'0,"

driven downwardly and the front staple is severed from the staple strip and moved downwardly, the severed staple is moved onto and against the forward end or terminal of the trigger 42. As the driving and setting plate moves toward its lowermost position, the arm 42 assumes the position shown in Fig. 6, in which it clears the driving and setting plate. As the driving and setting plate'is returned, as indicated in Fig. '7, the arm 42 and its supportingpin are cammed toward the rear against the tension of the spring 4|, as indicated in this figure. ting plate moves upwardly beyond the arm 42, the spring 4| operates to project the arm into its forward position, as indicated in Fig. 5.

The driving plunger C carries a manipulative head 50 which may be secured thereto as indicated. This plunger consists of an elongated member which may be rectangular in cross section, and which at its lower end is preferably provided with a notch defining a projection 5| to engage in a correspondingly shaped aperture in the driving and setting plate 41. The notch is deeper than the thickness of the driving and setting plate, and the parts are so constructed that when they are assembled in the machine the front face of. the driving and setting plate is located to the rear of the front face of the plunger to prevent any wear between these parts that might cause the plunger and driving and setting plate to jamat this point.

As shown, the driving plunger C is provided with a longitudinally extending slot 52 in which a return spring 53 is located. The upper end of the spring is seated on a member which comprises a cylindrical portion 54 which the spring encircles, and a head portion 55 which comprises a disk having opposite sides partly cut away to fit the walls of the grooves. The uncut portions provide shoulders 56 which are located at opposite sides of the disc constituting head portion 55 and engage the plunger, as indicated in Fig. 5, to hold the spring seat in assembled relation with the plunger.

The lower end of the spring rests on a spring seat and centering member 51 which is seated within the slot of the plunger andrests on the bottomwall 58 of a cylindrical recess 59 provided in the housing for the spring, and which is'intersected by the rectangular slot 60 in the housing in which the plunger C is guided and operates. The cylindrical portion 54 of the upper seat member engages the lower seat member to limit the downward movement of the driving plunger during the stapling operation, and the upward movement of the plunger is limited by means of a bolt 62 retained in place by a screw, as indicated in the various figures.

' The staple follower 20 may be of any desired or preferred construction, as shown. This follower is drawn forwardly'by the usual form of spring 6| which is housed in the head of the stapling arm, as indicated. For the purpose of anchoring and adjusting this spring, I have pro- As the driving and setvided a bolt 63 which is slotted as indicated at 64 to receive the end of the spring. This slot also constitutes a screw-driver engagement by means of which the spring may be tensioned. For the purpose of securely locking the bolt in position, I have provided the bolt with a taper 65 which may be drawn into tight engagement with the tapered aperture of the casing by means of the nut 66, thus securely locking the spring in adjusted position.

While the principles of this invention have been shown and described in connection with a specific embodiment thereof, the features of which have also been described in detail, it is to be understood that this has been done merely for the purposes of disclosure, and that words of descrip tion that may have been imported into the claims are to be considered as such and not as words of limitation, and that it is the intention to cover in the claims all equivalents as determined by the prior art.

What I claim is:

1. In a stapling machine including a stapling arm, a staple supporting rail of U-shaped cross section, a projection on said arm for cooperation with the inner surface of said U-shaped rail upon relative longitudinal movement of said arm and rail, and means for centering the front end of said rail with respect to said arm.

2. In a stapling machine including a stapling arm, a staple supporting rail of U-shaped cross section, a projection on said arm for cooperation with the inner surface of said U-shaped rail upon relative longitudinal movement of said arm and rail, and means for centering the front end of said rail with respect to said arm, said means comprising laterally extending shoulders supported by the front end of said rail.

3. In a stapling machine including a stapling arm, a staple supporting rail of U-shaped cross section, a projection on said arm for cooperation with the inner surface of said U-shaped rail upon relative longitudinal movement of said arm and rail, means for centering the front end of said rail with respect to said arm, said means comprising laterally extending shoulders supported by the front end of said rail, and means for holding the bight portions of said U-shaped rail and said stapling arm in spaced relation.

4. In a stapling machine, the combination of a stapling arm, a pivot pin, a staple guide rail, means on said arm and rail for interlocking engagement upon relative longitudinal movement, said rail being provided with elongated slots receiving said pivot pin permitting slight relative longitudinal adjustment of said rail and arm and said slots being of a width to engage said pin to position the rail vertically with respect to said arm, and a locating pin extending through the front ends of said rail and arm for positioning said arm and rail relatively longitudinally and the front ends thereof relatively vertically.

5. In a stapling machine, the combination of a stapling arm provided with a longitudinal groove provided at its front end with laterally communicating recesses, a staple supporting rail, a rear staple guide plate and a front staple guide plate in contact and engaging the side and rear walls of said recesses, and means interconnecting said rear guide plate and rail for positioning the rail within said groove in said arm.

6. A stapling arm return spring of flat stock comprising means adapted to rest on and be secured to the base of a stapling machine, an upwardly extending portion to engage a stapling arm, a continued downwardly extending portionto extend through a slot in the base of the machine, and a horizontally extending end on said last mentioned portion to engage the lower face of the top plate of the base.

7. A stapling machine comprising a stapling arm provided with a slot for guiding a driving plunger and with a shoulder in said slot, a driving plunger mounted in said slot provided with a longitudinal opening defining abutments, a coiled spring in said opening, seats for the ends of said spring, one of which is seated on the upper abutment of said plunger and the other of which is seated on said shoulder in the arm, means on said seats limiting the compression of. said spring, and means cooperating with the lower abutment to limit the return movement of said plunger.

8. In a stapling machine, the combination of a U-shaped stapling arm, av staple driving and setting plate slidably mounted in said arm, a staple supporting arm pivoted on said first mentioned arm at a point to the rear of said plate with its free end located in the path of travel of said plate, a pivot for said supporting arm mounted for bodily slidable movement in slots in said stapling arm, and spring means urging said arm forwardly and angularly into normal position.

' 9. In a stapling machine, the combination of, a base having a pivoted arm, a reciprocable plunger vertically guided in said arm and comprising a yoke having spaced upstanding members defining an elongated slot, a blade nonrotatably carried by said plunger, a stud nonrotatably connected to said members and disposed centrally of said slot, 2. stop transversely of said arm and disposed within said slot, said stop. cooperating with a lower portion of said yoke to limit upward displacement of. said plunger, abutment means within said slot and seated on the body of said arm for limiting downward displacement of said stud and a spring in part encircling said stud and abutment means for automatically raising said plunger.

10. In a stapling machine, the combination of, a base having a pivoted arm, a reciprocable plunger vertically guided in said arm and comprising a yoke having spaced upstanding members defining an elongated slot, a blade nonrotatably carried by said plunger, a stud non-rotatably connected to said members and disposed centrally of said slot, a stop transversely of said arm and disposed within said slot, said stop cooperating with a lower portion of said yoke to limit upward displacement of said plunger, abutment means within said slot and seated on the body of said arm for limiting downward displacement of said stud and a spring in part encircling said stud and abutment means adapted to automatically raise said plunger, a staple guiding rail centrally and longitudinally disposed within said arm, a race block carried by the forward end of. said rail, a channeled race block interposed between said first mentioned race block and a forward wall of said arm, said race blocks cooperating to define a vertical raceway for slidably and Vertically guiding a, staple ejected therein by said blade.

11. In a stapling machine, the combination of, a base having a pivoted arm, a reciprocable plunger vertically guided in said arm and comprising a'yo-ke having spaced upstanding members defining an elongated slot, a blade nonrotatably carried by said plunger, a stud nonrotatably connected to said members and disposed centrally of said slot, a stop extending transversely of said arm and-disposed within said slot, said stop cooperating with a lower portion of said yoke to limit upward displacement of said plunger, abutment. means within said slot and seated on the body of said arm for limiting downward displacement of said stud, and a spring in part encircling said stud and abutment means adapted to automatically raise said plunger, a staple guiding rail centrally and longitudinally disposed within said arm, a vertically arranged race block carried by said forward end of said arm, a channeled race block vertically interposed between said first mentioned block and a forward wall of said arm, said race blocks having marginal juxtapositioned transversely disposed surfaces in contact, said blocks cooperating to define a vertical raceway for slidably guiding a staple ejected therein by said blade.

12. In a stapling machine, a pivoted arm having a staple supporting rail and means constituting a vertically disposed raceway, a staple driving reciprocable blade movably guided in said raceway, fulcrum means movably carried by said rail, a pin secured to said arm, staple supporting means having an intermediate portion mounted on said fulcrum means and comprising a terminal adapted to project into said raceway, and a depending tail portion, and spring means interconnecting said pin and said tail portion. a

13. In a stapling machine, a pivoted arm having a staple supporting rail and means constituting a vertically disposed raceway, a spring controlled plunger having a blade movably guided in said raceway, said rail having depending sides having alined relatively elongated openings, fulcrum means movably guided in said alined openings, a pin secured to said arm; staple supporting means having a terminal portion projecting into said raceway in a raised position of said blade, an intermediate curved portion in part en compassing said fulcrum means and movable relative thereto, and a tail portion disposed out of alinement with said terminal portion; and a spring interconnecting said pin and tail, portion.

14. In a stapling machine, a pivoted arm having a staple supporting rail and means constituting a vertically disposed'raceway, a spring controlled plunger having a blade movably guided in said raceway, said rail having depending sides having alined relatively elongated openings, fulcrum means movably guided in said alined openings, a transverse pin fixedly secured to said arm; staple supporting means pivotally mounted on said fulcrum means and comprising a terminal adapted to project into said raceway, an intermediate bearing portion rotatably mounted on said fulcrum means, and a depending tail portion; and spring means interconnecting said tail portion and said pin, said fulcrum means being disposed at corresponding forward portions of said openings during pivotal displacement of said terminal during descent of said blade, said spring means expanding during downward displacementof said blade, said terminal being disposed at the rear face of said blade towards the completion of the downward displacement of said blade; said terminal elevating in contact with said rear face during the elevation of said blade for actuating said bearing to rearwardly displace said fulcrum means in said alined openings, said spring means causing said terminal to project into said raceway when said blade is above and free of said terminal, said spring means upon contraction thereof urging said tail portion to permit said bearing to shift said fulcrum means against said forward portions of said alined openings.

r 15. In a stapling machine, ,a pivoted arm having a staple supporting rail and means constituting a vertically disposed raceway, a spring controlled plunger having a blade movably guided in said raceway, said rail having depending sides having alined relatively elongated openings, fulcrum means movably guided in said alined openings, a transverse pin fixedly secured to said arm; staple supporting means pivotally mounted on said fulcrum means and comprising a terminal adapted to project into said raceway, an intermediate bearing portion rotatably mounted on said fulcrum means, and a depending tail portion, and helicoidal spring means interconnecting said tail portion and said pin, said staple supporting means merely pivoting during downward displacement of said blade, said fulcrum means being disposed at corresponding forward portions of said openings during pivotal displacement of said staple supporting means during descent ,of said blade, said'spring means expanding during downward displacement of said blade, said terminal being disposed at the rear face of said blade towards the completion of the downward displacement of said blade; said terminal portion elevating in contact with said rear face during the-elevation of said blade for actuating said bearing to rearwardly displace said fulcrum means in said alined openings, said spring causing said terminal to project into said raceway when said blade is above and free of said terminal, said spring 'upon contraction thereof urging said tail portion to permit said bearing to shift said fulcrummeans against said forward portions of said alined openings.

. 16. In a stapling machine, a pivoted arm having a staple supporting rail and means constituting a vertically disposed raceway, a depressible staple driving blade movably guided insaid raceway, fulcrum means extending between the sides of said rail and in part disposed within the latter, a fixed pin spaced from 'said fulcrum means and disposed in part within and transversely of said rail, staple supporting means pivotally supported by said fulcrum means and comprising a relatively elongated member interposed between the sides of said rail and having a portion contacting said fulcrum means and a rearwardlydisposed depending portion and a forwardly dis-1 posed staple supporting terminal adapted to project into said raceway, and spring means interconnecting said fixed pin and said depending portion and normally adapted to hold said terminal. in an elevated position in said raceway when said blade is in an elevated position. i

17. In a stapling machine, a base, an arm pivoted to said base and having a staple supporting rail and means constituting a vertically disposed on said fulcrum means and including a depending part, saidelongated member having a forwardly spo e offset Po t n in u in a staple upporting terminal disposed below the body of said member and adapted to project in said raceway in an elevated positionthereof, and spring means interconnecting said depending part and said fixed pin for holding the forward part of said terminal above the elevation of said fixed pin and within said raceway in a raised position of said blade. V

18. In a staplin' machine, a base; an arm pivoted to sa d base and having a staple supporting rail and means constituting a vertically disposed raceway, a reciprocable staple driving blade movably guided in said raceway and adapted to eject a staple therefrom, fulcrum means interposed between the sides of said rail and disposed within the latter and transversely thereof, a fixed pin disposed forwardly of and spaced from said fulcrum means and arranged in part within and transversely of said rail, and staple supporting means having a rear part pivotally sustained by said fulcrum means and comprising a relatively elongated member interposed between the sides of said rail and having a rearwardly disposed depending portion and a forwardly extending offset portion including a staple supporting terminal disposed below the body of said member and adapted to project in said raceway in an elevated position of said blade, and a helicoidal spring interconnecting said depending portion and said fixed pin for holding the forward part of said offset portion elevated and in part within said raceway in a raised position of said blade.

19. In a stapling machine, a base, an arm pivoted to said base and having a staple supporting rail and means constituting a vertically disposed raceway, a reciprocable staple driving blade movably guided in said raceway for ejecting a staple therefrom, fulcrum means interposed between the sides of said rail and disposed within the latter and transversely thereof, a fixed pin disposed forwardly of and spaced from said fulcrum means and arranged in part within and transversely of said rail, staple supporting means having a rear part pivotally sustained by said fulcrum means and comprising a relatively elongated member interposed between and movably guided by the sides of said rail and having a rearwardly disposed depending portion and a forwardly disposed offset portion including a staple supporting terminal disposed below said body of said member and adapted to project in said raceway in an elevated position of said body, and spring means interconnecting said depending portion and fixed pin for holding said terminal in part within said raceway in a raised position of said blade, said blade on downward displacement thereof relative to said raceway cooperating with said terminal to move the latter downwardly and rearwardly relative to the raceway concomitantly pivoting said member against the resistance of the expansion of said spring means whereby said terminal portion is moved out of said raceway and in back of said blade.

20. In a stapling machine, a base, an arm pivoted to said base and having a staple supporting rail, a race block mounted at the forward part of said rail and including a vertically disposed slot, a reciprocable staple driving blade movably guided in said arm, fulcrum means interposed between the sides of said rail and disposed within the latter and transversely thereof, a pin spaced from said fulcrum means and disposed in part within and transversely of said rail, staple supporting means having a rear part pivotally sustained by saidiulcrum means and comprising a relatively elongated member movably interposed between and guided by the sides ofsaid rail and having a rearwardly disposed depending portion disposed at the rear of and adjacent said fulcrum means and a forwardly disposed offset portion including a staple supporting terminal disposed below the body of said member and adapted to extend within and'project beyond said slot in an elevated-position-of said blade and spring means-interconnecting said depending portion and pin for holding said terminal elevated to project beyond said slot and slightly overhang said block in a raised position of said blade, said blade on downward displacement thereof relative to said block cooperating with said terminal to pivot said staple supporting means and move said terminal downwardly and rearwardly relative to said block to be substantially within said slot and in back of said blade, said blade during elevation thereof cooperating with said terminal to elevate the latter, said spring means upon the elevation of said blade above said terminal causing said terminal to project beyond said slot to slightly overhang the forward face of said block.

21. In a stapling machine, a base, an arm pivoted to said base and having a staple supporting rail and means constituting a vertically disposed raceway, a reciprocable staple driving blade movably guided in said raceway for ejecting a staple therefrom, fulcrum means interposed between the sides of said rail and disposed within the latter and transversely thereof, a fixed pin disposed forwardly of and spaced from said fulcrum means and arranged in part within and transversely of said rail, staple supporting means having a rear part pivotally sustained by said fulcrum means and comprising a relatively elongated member interposed between and movably guided by the sides of said rail and having a rearwardly disposed depending portion disposed in back of said fulcrum meansbut adjacent thereto and a forwardly disposed offset portion including a staple supporting terminal disposed below the body of said member and adapted to project in said raceway in. an elevated position of said body, and spring means interconnecting said depending portion and fixed pin for holding said terminal in part within said raceway in a raised position of said blade, said blade on downward displacement thereof relative to said raceway cooperating with said terminal to move the latter downwardly and rearwardly relative to said raceway and concomitantly pivoting said member against the resistance of said spring means where-- by said terminal portion is moved out of said raceway and in back of said blade, said spring means upon the elevation of said blade above said terminal causing said terminal to project beyond and slightly overhang said raceway.

22. In a stapling machine, a base, an arm pivoted to said base and having a staple supporting rail and means constituting a vertically disposed raceway, a reciprocable staple driving blade movably guided in said raceway for ejecting a staple therefrom, fulcrum. means interposed between the sides of said rail and disposed within the latter and transversely thereof, a fixed pin disposed forwardly of and spaced from said fulcrum means arranged in part within and transversely of said rail, staple supporting means having a rear part pivotally sustained by said fulcrum means and comprising a relatively elongated member interposed between and movably tive to said'raceway cooperating with said terminal to' move the latter downwardly and rearwardly relative to said raceway concomitantly pivoting said member against the resistance of the expansion of said spring means whereby said terminal portion is moved out of said raceway and in back of said blade, said blade during elevation thereof cooperating with said terminal to elevate the latter, said spring means upon the elevation of said blade above said terminal causing said terminal to project within said raceway.

. STEPHEN A. CROSBY. 

